The present invention is related to an improved method for making aliphatic diperoxyacids having from about 12 to about 20 carbon atoms.
Peroxygen bleaching agents in general and peroxyacid compounds in particular have long been recognized as effective bleaching agents for use when the adverse color and fabric damage effects of harsh halogen active bleaching agents cannot be tolerated. See, for example, Canadian Pat. No. 632,620, Jan. 30, 1962, to McCune. This attractive nature of peroxy-acid compounds makes it desirable to be able to make them in the most economical manner.
The prior art teaches the making of peroxyacid compounds in several ways. Parker et al in Journal American Chemical Society, 79, 1929 (1957), disclose making diperoxyacids by dissolving a dibasic acid in sulfuric acid and adding hydrogen peroxide dropwise. U.S. Pat. No. 3,079,411, Feb. 26, 1963, to Silbert et al., discloses forming long chain aliphatic peroxyacids by combining an aliphatic acid with an alkanesulfonic acid and then treating the combination with an excess of hydrogen peroxide. U.S. Pat. No. 2,813,896, Nov. 19, 1957, to Krimm, discloses forming peroxyacids by combining sulfuric acid and hydrogen peroxide and subsequently treating the combination with carboxylic acid. The reaction is conducted so that there is at least one mole of sulfuric acid present at the end of the reaction for every six moles of water.
While the prior art teaches several methods for making peroxyacids, it does not indicate what problems are involved with making long chain peroxyacids. It has been found that using the prior art methods, such acids are formed slowly or in very small, difficult to filter crystals.
It is an object of the present invention to provide a method for making diperoxyacids which overcomes the above problems. Specifically, the present invention provides a method whereby diperoxyacids can be made much quicker than prior art methods or in larger, easier to filter crystals.
These and other objects of the present invention will become apparent from the following description.
All percentages and ratios used herein are by weight unless otherwise specified.